I had to make a decision between two schools, and chose the one I felt was a better fit from me. So I signed my letter and sent it in by April 15th.
I just found out that I was accepted and fully funded to my top choice school! I'm almost positive I want to go to this school. Is it ok to decline the other offer, even after I signed the letter? Also, what is the most appropriate way to notify the school? A short and sweet e-mail or a phone call??